This invention relates to apparatus used to straighten vehicle chassis of automobiles, vans, SUV""s, trucks and other vehicles and, more particularly, to vehicle-straightening benches having platforms for supporting and anchoring vehicles while pulling assemblies apply forces at desired locations and in desired directions thereby restoring the vehicle chassis to original configurations.
Occasionally, vehicles are involved in collisions, and before they can reenter meaningful service, the vehicle chassis must be returned, as nearly as possible, to their original configurations. This is frequently accomplished with straightening benches. A typical straightening bench includes a platform for supporting and anchoring a vehicle chassis while forces are applied to the chassis by pulling assemblies. The pulling assemblies utilize hydraulically powered telescoping towers with chains that attach to desired locations on the vehicle chassis. To hold them in place, the pulling assemblies are secured to the bottom of the platform while force is applied to the chassis. In many designs the pulling assemblies are permanently mounted to the bottom side of the platform. With the pulling assemblies mounted on the platform, the large hydraulic pulling forces exerted by the towers create even larger moments and forces where the pulling assemblies are mounted to the platform. Thus, the pulling assembly mounts must be excessively over designed and occasionally fail rendering the pulling assembly inoperable. Further, the pulling assembly mounts unduly limit the possible positions of the pulling assemblies and hence restrict an operator""s ability to apply force in any desired direction.
Many straightening benches utilize platforms, which can be raised and lowered with hydraulic lifts. Typically, the same hydraulic pump is used to power both the platform lift and the pulling assemblies. However, there are competing hydraulic design criteria for the lifts and the pulling assemblies. For the lifts, it is desirable to have a high volume pump, so that the lift does not operate too slowly, but the high-force pulls need more control requiring a low volume pump. More simply put, the lift should operate relatively fast and the towers of the pulling assemblies should operate relatively slow. To date, no satisfactory solution has been presented for these competing hydraulic design criteria. Additionally, prior straightening benches have lacked sufficient automation of locking mechanisms, and operators have been required to manually release valves and lock mechanism, which places the operators dangerously close to the straightening bench.
There is therefore provided in the practice of the invention a novel vehicle-straightening bench which provides increased versatility, improved force control, and enhanced safety, for straightening vehicle chassis by the measured application of hydraulic force to the vehicle chassis. The vehicle straightening bench broadly includes a vehicle platform operable to support a vehicle chassis and an anchor attachable to the platform for securing the vehicle chassis to the platform. A pulling tower is provided to apply force to the vehicle chassis. A carriage assembly is moveably received by a carriage track, which is mounted on the platform, and the pulling tower is mounted on the carriage assembly.
In a preferred embodiment, the pulling tower is pivotally mounted on the carriage assembly, and the carriage assembly includes a tower positioning mechanism. The tower positioning mechanism engages a tower arm which extends between the pulling tower and the carnage assembly to mount the pulling tower to the carriage assembly. The positioning mechanism holds the pulling tower in a transport position substantially perpendicular to the bench while the pulling tower and carriage assembly are moved along the carriage track. The preferred positioning mechanism includes a pawl follower fixedly mounted on the tower arm and a notch plate mounted on the carriage assembly. The notch plate defines a notch, which receives the pawl follower, so that the pulling tower is substantially perpendicular to the bench when the pawl follower is received in the notch. A pawl biasing member, which is preferably a pawl spring, engages the pawl follower and forces it toward the notch plate and into the notch to hold the pulling tower in the transport position.
Preferably, the carriage assembly includes a carriage body defining a lock pin opening and further comprises a locking mechanism having a lock pin moveably received in the lock pin opening. A lock pin biasing member, preferably a compression spring, also received in the lock pin opening, engages the lock pin to bias the lock pin into an extended locking position. Once the lock pin is in the locking position, which locks the carriage assembly in place relative to the vehicle platform and carriage track, an operator applying a force will overcome the pawl biasing member thereby forcing the pawl out of the notch and pivoting the pulling tower relative to the carriage assembly. Preferably, the lock pin is coaxial with the pivot axis of the pulling tower. The locking mechanism also includes a release handle operative to release the lock pin when moved vertically downward.
A preferred carriage assembly includes a generally trapezoidal carriage body having a inwardly facing narrow end and an outwardly facing wide end. A single inner wheel is mounted on the narrow end of the carriage body for engaging the platform adjacent an inner rail of the carriage track. Two outer wheels are supported on an outer rail of the carriage track. The outer wheels preferably include circumferential ridges, which engage a wheel slot defined by the outer rail. Further, a guide is forced against the outer rail by a guide spring, and a pair of guide rollers are positioned adjacent the outer wheels. Preferably, the carriage assembly alone supports the pulling tower above the ground surface.
In another aspect of the invention, the bench utilizes a force arm which has one end substantially fixed to the pulling tower and a free end capable of pivoting in three dimensions relative to the pulling tower. The force arm is preferably telescoping and includes a pivoting anchoring foot configured for insertion in anchoring apertures defined in the platform. The pivoting anchoring foot rotates to lock in the platform anchoring apertures. The force arm provides additional support to the pulling tower and carriage assembly when hydraulic force is applied to the vehicle chassis by the pulling tower.
In still another aspect of the invention, the vehicle-straightening bench utilizes a moveable crossmember extended between inner sides of opposed legs of the vehicle-straightening bench. Opposite ends of the crossmember slideably engage slide tracks formed on the inner sides of the opposed legs of the bench. Two position locks are located at the ends of the crossmember and are operable to lock the crossmember in a selected position on the bench. The slide tracks define lock openings and each position lock includes a pivotally mounted lock rod. A rod biasing member forces the lock rods into the lock openings defined in the leg tracks to hold the crossmember in position.
In still another aspect of the present invention, the vehicle-straightening bench preferably includes a hydraulic control circuit. In a preferred embodiment of the bench having front and rear lifts, the hydraulic control circuit includes front and rear sets of lift control valves operative to actuate the front and rear lifts independently and/or simultaneously. A tower control valve is also provided which in conjunction with the front and rear lift control valves is operable to permit actuation of the pulling tower only when the lift control valves are closed. The bench also preferably includes a pneumatic control circuit with first and second pneumatic cylinders operable to move first and second lift latches which engage the lifts to lock them in desired positions. A remote control is provided to operate both the pneumatic and hydraulic control circuits. The control system utilizes a programmable logic controller to transmit instructions to the respective valves and cylinders.
Accordingly, it is an object of the present invention to provide an improved vehicle-straightening bench for straightening vehicle chassis.
It is another object of the present invention to provide an improved carriage assembly for movement and increased positioning versatility of pulling towers around a vehicle-straightening bench.
It is still another object of the present invention to provide an improved vehicle straightening bench control circuit for remote actuation of valves and cylinders.
It is a further object of the present invention to provide an improved pulling assembly having an additional force transmission path between a pulling tower and a vehicle platform of a vehicle-straightening bench.